[0001] This invention is concerned with liquid compositions containing stable, water-dispersible,
electrically-charged and highly fabric-substantive aminoplast microcapsules that are
essentially free of bound and free formaldehyde.
[0002] It is well known that ingredients such as fragrances, insecticides, malodour counteracting
substances, fungicides and mildewicides, and the like may be encapsulated in a microcapsule
comprising a solid shell or membrane, which protects them from their immediate environment
and acts as means for their controlled release. A popular and convenient method of
producing such encapsulated formulations consists of dispersing the ingredient in
a liquid and creating a polymeric membrane on the surface of the droplets.
[0003] A much-used way of doing this is by means of the interfacial polycondensation of
various co-monomers and macromers. The polycondensation of amine compounds such as
urea and melamine (2,4,6-triamino-1,3,5-triazine) with formaldehyde to form so-called
aminoplast microcapsules is the most popular among these processes, leading to shells
consisting of highly cross-linked resins (also known as thermoset resin).
[0004] These established processes essentially convert emulsions consisting of a dispersed
oil phase containing the ingredient to be encapsulated and a continuous water phase
into a suspension of solid beads consisting of a core surrounded by a membrane, whose
permeability depends on a number of factors, including the extent of cross-linking,
and/or the thickness of said membrane.
[0005] When applied to fragrances, these microcapsules are typically used for generating
surprising sensory effects, such as an increased perfume intensity, or impact, at
some point in time when the microcapsules are broken by the action of pressure or
rubbing. This strategy is used in so-called "scratch-and-sniff" systems. They are
often used in conjunction with non-encapsulated perfume in consumer products.
[0006] Melamine-formaldehyde resins are especially suitable for perfume encapsulation, because
of their remarkable property of providing highly cross-linked networks capable of
retaining small molecules, such as those encountered in perfumes. Furthermore, microcapsule
shells comprising aminoplast terpolymer, containing polyol moieties, and especially
aromatic polyol moieties provide excellent perfume retention, even under drastic storage
conditions, such as those encountered during the storage of consumer products containing
high levels of surfactants.
[0007] WO 2006/129252 A2 discloses microcapsules comprising a core of perfume and an aminoplast shell being
the reaction product of an amine such as urea, thiourea or melamine and formaldehyde.
[0008] However, melamine-formaldehyde microcapsules contain free formaldehyde, either due
to unreacted formaldehyde precursors and/or generated during storage of the microcapsules,
especially in acidic conditions. Formaldehyde is a very undesirable substance, and
its emission should be minimal, preferably non-existent. The traditional way of combating
this has been the use of formaldehyde scavengers, compounds able to react with formaldehyde
to form a stable condensate. Examples include urea, amino acids, beta-keto esters
and ethylene urea. However, these can affect the integrity of the microcapsule shell.
[0009] It has now been found that it is possible to prepare melamine-based microcapsules
comprising an aminoplast terpolymer containing polyol moieties, and especially aromatic
polyol moieties, which is essentially free of formaldehyde, while still being highly
cross-linked, and thereby offering high perfume retention, even under drastic storage
conditions, such as prolonged exposure to storage temperatures as high as 45 °C and
in the presence of high levels of surfactants.
[0010] There are therefore provided microcapsules comprising a core of fragrance and a shell
of aminoplast polymer, the composition of the shell being from 75-100% of a thermoset
resin comprising 50-90%, preferably from 60-85%, of a terpolymer and from 10-50%,
preferably from 10-25%, of a polymeric stabilizer; the terpolymer comprising:
- (a) from 20-60%, preferably 30-50% of moieties derived from at least one polyamine;
- (b) from 3-50%, preferably 5-25% of moieties derived from at least one polyol; and
- (c) from 20-70%, preferably 40-60% of substituted methylene moieties,
the microcapsules additionally optionally comprising up to 25%, preferably up to 10%
of a cationic polymer.
[0011] The substituted methylene moieties are as defined in claim 1.
[0012] In this description, unless otherwise specifically stated, all percentages are by
weight.
[0013] By "moiety" is meant a chemical entity, which is part of the terpolymer and which
is derived from a particular molecule. The terpolymer hereinabove described may be
any terpolymer comprising the moieties hereinabove described, and it may be prepared
by any of the many suitable methods known to the art.
[0014] The use of the term "derived from" does not necessarily mean that the moiety in the
terpolymer is directly derived from the substance itself, although this may be (and
often is) the case.
[0015] Examples of suitable polyamine moieties include, but are not limited to, those derived
from urea, melamine, 6-substituted-2,4-diamino-1,3,5 triazin, such as benzoguanamine,
and glycoluril.
[0016] Polyol moieties may be selected from aromatic, aliphatic and polymeric polyol moieties.
Examples of suitable aromatic polyol moieties include, but are not limited to, those
derived from, or having the form of those derived from, phenol, 3,5-dihydroxy toluene,
Bisphenol A, resorcinol, hydroquinone, xylenol, polyhydroxy naphthalene and polyphenols
produced by the degradation of cellulose and humic acids. Examples of suitable aliphatic
polyols include, but are not limited to 2,2-dimethyl-1,3-propane diol, 1,1,1-tris-(hydroxymethyl)-propane,
pentaerythritol, sorbitol, sugars and the like.
[0017] The substituted methylene moieties have the general formula (1)
where R is either a hydrogen atom or an alkyl group and Y
1 and Y
2 are substituents selected from sigma acceptor groups, alkyne groups and metal sulphonates.
By "sigma acceptor group" is meant a group that induces a partial positive charge
on the carbon atom adjacent to it (by polarization of the sigma orbital involved in
the carbon-Y bond) in such a way that a positive charge appears. Examples of such
groups include hydroxyl, alkoxide, phenyl-oxy, alkyl and aryl carboxylate, cyano,
phenyl and substituted phenyl.
[0018] Such substituted methylene moieties are thus either terminal groups on polymer chains
(when OR is present) or crosslinking moieties, when the bonds remote from the Y
1, Y
2 moieties are both attached to polymers.
[0019] Binding of the substituted methylene to the polymer occurs via the formation of either
a carbon-nitrogen bond with the polyamines, or carbon-carbon or carbon-oxygen bond
with the polyols.
[0020] The substituted methylene moieties may be derived from compounds having the general
formula (2) or (3).
where R1 is either a hydrogen atom or an alkoxide group, and Y
1 and Y
2 are substituents selected from sigma acceptor groups, as hereinabove defined, or
alkyne groups, or metal sulfonates. Examples of substances corresponding to formula
(2) are ethyl 2-ethoxy -2-hydroxy acetate, methyl 2-hydroxy-2-methoxy acetate and
corresponding alkylated variants with C3 to C6 alkyl chains, 2,2-dimethoxy-acetic
acid methyl ester, 2,2-diethoxyacetic acid ethyl ester and corresponding alkylated
variants with C3 to C6 alkyl chains, 2,2-dimethoxy ethanal, di-phenoxy ethanal.
[0021] In a specific embodiment, substances of formula (2) are obtained from the reaction
of resorcinol with glyoxylic acid.
[0022] The polymeric stabilizer prevents the microcapsules from agglomerating, thus acting
as a protective colloid. It is added to the monomer mixture prior to polymerisation,
and this results in its being partially retained by the polymer, while another part
passes into the continuous phase.
[0023] Particular examples of suitable polymeric stabilizers include acrylic copolymers
bearing sulfonate groups, such as those available commercially under the trade mark
LUPASOL (ex BASF), such as LUPASOL PA 140 or LUPASOL VFR; copolymers of acrylamide
and acrylic acid, copolymers of alkyl acrylates and N-vinylpyrrolidone, such as those
available under the trade mark Luvislcol (e.g. LUVISKOL K 15, K 30 or K 90 ex BASF);
sodium polycarboxylates (ex Polyscience Inc.) or sodium poly(styrene sulfonate) (ex
Polyscience Inc.); vinyl and methyl vinyl ether - maleic anhydride copolymers (e.g.
GANTREZ AN, ex ISP), ethylene, isobutylene or styrene-maleic anhydride copolymers,
and methyl vinyl ether - maleic acid copolymers (GANTREZ S, ex ISP). Hence the preferred
polymer stabilizers are anionic or anionogene polyelectrolytes.
[0024] Optionally, the microcapsules may be coated with a cationic polymer. The cationic
polymer allows partial or complete neutralization of the negative electrical charge
borne by the microcapsules, or even the conversion of the negatively-charged microcapsules
into positively-charged microcapsules.
[0025] Preferred cationic polymers comprise cationic cellulose derivatives, such as those
available under the Trade Mark UCARE (ex Amerchol), and quaternized gums, such as
quaternized guar gums available under the Trade Mark JAGUAR (ex Rhodia), polyethylene
imine, such as those available commercially under the Trade Mark LUPASOL (ex BASF),
cationic polyacrylates and acrylamides , gelatine and quaternized protein hydrolysates,
and quaternized amino silicones.
[0026] Other cationic compounds that can be used include the Polyquaternium range, all of
which have a plurality of quaternary ammonium groups, polymeric species such as diallyl
dimethyl ammonium chloride/acrylamide polymers, for example, those available under
the Trade Mark MERQUAT (ex Nalco), and copolymers of vinyl pyrrolidone and quaternized
dimethylaminoalkyl methacrylate, for example, those available under the Trade Mark
GAFQUAT HS 50 and HS 100 (ex ISP).
[0027] Microcapsules of the type hereinabove described are provided in the form of aqueous
slurry, having typically 15 to 50% solids content, where the term "solids content"
refers to the total weight of the microcapsules. The average size of the microcapsules
may range between 1 micrometer to 100 micrometers, or more, depending on the mixing
shear stress applied to the system during microcapsule formation. The selection of
the most appropriate microcapsule size range and size distribution depends on the
application envisioned. In the case where the microcapsules are used in laundry products,
it has been found that microcapsules having size ranging from 5 to 60 micrometers
offer optimal performance in terms of deposition and olfactive impact when rubbed
with small to moderate shear stress.
[0028] The slurry may contain formulation aids, such as stabilizing and viscosity control
hydrocolloids, and biocides.
[0029] Typically, hydrocolloids are used to improve the colloidal stability of the slurry
against coagulation, sedimentation and creaming. The term "hydrocolloid" refers to
a broad class of water-soluble or water-dispersible polymers having anionic, cationic,
zwitterionic or non-ionic character. Hydrocolloids useful for the sake of the present
invention encompass: polycarbohydrates, such as starch, modified starch, dextrin,
maltodextrin, and cellulose derivatives, and their quaternized forms; natural gums
such as alginate esters, carrageenan, xanthanes, agar-agar, pectines, pectic acid,
and natural gums such as gum arabic, gum tragacanth and gum karaya, guar gums and
quaternized guar gums; gelatine, protein hydrolysates and their quaternized forms;
synthetic polymers and copolymers, such as poly(vinyl pyrrolidone-co-vinyl acetate),
poly(vinyl alcohol-co-vinyl acetate), poly((meth)acrylic acid), poly(maleic acid),
poly(alkyl(meth)acrylate-co-(meth)acrylic acid), poly(acrylic acid-co-maleic acid)copolymer,
poly(alkyleneoxide), poly(vinylmethylether), poly(vinylether-co-maleic anhydride),
and the like, as well as poly-(ethyleneimine), poly((meth)acrylamide), poly(alkyleneoxide-co-dimethylsiloxane),
poly(amino dimethylsiloxane), and the like, and their quartenized forms;
[0030] The microcapsules according to the invention are further characterized by a nominal
shell to core mass ratio lower than 15%, preferably lower than 10% and most preferably
lower than 5%. Hence, the microcapsules may have extremely thin and frangible shells.
[0031] The shell to core ratio is obtained by measuring the effective amount of encapsulated
perfume oil microcapsules that have been previously washed with water and separated
by filtration. This is achieved by extracting the wet microcapsule cake by microwave-enhanced
solvent extraction and subsequent gas chromatographic analysis of the extract.
[0032] Compared to the aminoplast microcapsules of the prior art, the microcapsules and
microcapsule slurries of the present invention display the advantage of being essentially
free of free or nascent formaldehyde. This means that, when added to and stored over
months in acidic consumer products, said microcapsules and slurries do not release
free formaldehyde. The use of formaldehyde scavengers is therefore not required.
[0033] Furthermore, the use of an aminoplast terpolymer containing polyol moieties, and
especially aromatic polyol moieties, leads to a number of unexpected advantages compared
to the prior art, for example.:
- the microcapsules have the ability to accommodate a much wider range of fragrance
compositions than has previously been the case, including fragrance compositions whose
encapsulation has been difficult or even impossible by known methods,
- the overall amount of shell material required to build up a stable microcapsule is
considerably reduced, leading to thinner capsule walls and much better frangibility
to stability balance than has been hitherto achievable. This leads to a surprisingly
high perfume retention, compared to the very small thickness of the microcapsule wall,
- the microcapsules are much less prone to plasticization by external, non-encapsulated
fragrances,
- the microcapsules can be used in the anionic form, i.e. without any cationic coating,
in fabric care conditioners, without impeding their substantivity on cotton, polyester
and other fabrics. This is a surprising results, which cannot be anticipated from
the prior art.
[0034] In a particular embodiment, the microcapsule slurry according to the invention is
furthermore capable of releasing electrically-charged microcapsules, characterized
by an absolute zeta-potential ranging from 0.1mV to 100 mV when dispersed in deionised
water.
[0035] By "zeta-potential" (ζ) is meant the apparent electrostatic potential generated by
any electrically charged objects in solution, as measured by specific measurement
techniques. A detailed discussion of the theoretical basis and practical relevance
of the zeta-potential can be found, e.g., in "
Zeta Potential in Colloid Sciences" (Robert. J. Hunter; Academic Press, London 1981,
1988). The zeta-potential of an object is measured at some distance from the surface of
the object and is generally not equal to and lower than the electrostatic potential
at the surface itself. Nevertheless, its value provides a suitable measure of the
capability of the object to establish electrostatic interactions with other objects
present in the solution, such as surfactants, polyelectrolytes and surfaces.
[0036] The zeta-potential is a relative measurement and its value depends on the way it
is measured. In the present case, the zeta-potential of the microcapsules is measured
by the so-called phase analysis light scattering method, using a ZetaPALS instrument
(ex Brookhaven Instruments Corporation). The zeta-potential of a given object may
also depend on the quantity of ions present in the solution. The values of the zeta-potential
specified in the present application are measured in deionised water, where only the
counter-ions of the charged microcapsules are present.
[0037] By "absolute zeta-potential" (|ζ|) is meant the absolute value of the zeta-potential
without reference to its (positive or negative) sign. Hence, negatively-charged objects
having a zeta-potential of -10 mV and positively charged species having a zeta-potential
of +10 mV have the same absolute zeta-potential.
[0038] In a particular embodiment, a composition utilising the microcapsules hereinabove
described is characterized by its ability to deliver microcapsules for fabric care
conditioners, the microcapsules having a negative zeta-potential ranging from - 0.1
mV and - 100 mV when dispersed in deionised water.
[0039] The microcapsules are highly frangible, by which is meant the ability of the dry
microcapsules according to the invention to break and release the encapsulated perfume
under the action of a normal bursting force not superior to 9 mN for microcapsules
having a diameter of 60 micrometers and not superior to 3 mN for microcapsules having
a diameter of 35 micrometers, which corresponds to a bursting pressure not higher
than 6 x 10
6 MPa. Typically, the bursting pressure of microcapsules according to the present invention
does not exceed 1 to 10 MPa, preferably 4 to 7 MPa. Both bursting force and bursting
pressure may be measured by various methods, such as a nano-indentation test, or an
osmotic rupture test. These aforementioned forces refer to the ones currently applied
to a garment when it is folded, put on, worn or taken off.
[0040] A typical nano-indentation test is conducted as follows: the slurry of suspended
microcapsules is diluted with deionized water and applied on to a polished and (N
2/O
2) plasma-cleaned aluminum holder. After evaporation of the water, the holder having
discrete microcapsules on its surface is transferred to a MTS Nanoindenter XP equipped
with a 60 micrometer diamond flat top indenter body. All compression tests are performed
under controlled displacement mode with a displacement rate of 100 nanometer/sec.
The load vs. displacement curves are measured to obtain the bursting force (
Fcrit) and critical displacement (
hcrit) at rupture.
[0041] By "dry microcapsule" is meant microcapsules that have been submitted to usual drying
conditions such as those prevailing during line drying or tumble drying.
[0042] Perfume-containing microcapsules for use in liquid, aqueous fabric care conditioners
constitute a particular embodiment of the present invention and are typically obtained
by the following process:
- 1. Forming an oil-in-water emulsion of perfume under moderate to high shear stirring
in the presence of polymer stabilizer, whereby the stirring speed and the geometry
of the mixer is defined as a function of the desired average microcapsule size range
and microcapsule size distribution. These maters are well within the ordinary skill
of the art.
- 2. Adding the polyamine and at least one substituted methylene compound as hereinabove
described,
- 3. Adjusting the pH to a range of 1 to 7, depending on the reactivity of the substituted
methylene compound, by adding a Bronsted acid, such as sulphuric acid, sulfonic acid,
hydrochloric acid, formic acid, and the like;
- 4. While performing Step 3, adding aromatic polyol to the reaction medium, at the
beginning, the end or continuously during Step 3; this forms the microcapsule shell,
- 5. Heating at a temperature ranging from 75 °C to 90 °C for 1 to 5 hours to cure the
shell,
- 6. Cooling the system to room temperature.
[0043] In a typical composition according to the invention, the typical amount of perfume
oil added to the reaction medium that forms the terpolymer is between 15 and 50 wt%,
preferably between 25 and 40 wt%, most preferably between 35 and 40 wt% of the total
mix. The composition range of the other ingredients entering in the microencapsulation
is given below for a nominal perfume concentration of 38 wt%. However, it will be
obvious of anybody skilled in the art that modifying this nominal perfume oil level
will require optimization of the levels of the other ingredients.
[0044] Hence, for a nominal perfume oil concentration of 38 wt%, the composition of the
remaining ingredients in the reaction medium will preferably be as follows:
- 1 to 10 wt%, preferably 2 to 8 wt% and most preferably 3 to 4 wt% of polyamines,
- 0.1 to 3 wt%, preferably 0.3 to 2 wt% and most preferably 0.5 to 1.5 wt% of aromatic
polyols,
- 1 % to 10 % wt%, preferably 2 % to 8 % wt% and most preferably 3% to 4 % of substituted
methylene compound,
- 0.1 to 3 wt%, preferably 0.3 to 2 wt% and most preferably 0.5 to 1.5 wt% of stabilizing
polymer.
the balance being water.
[0045] Fragrance materials for use in compositions of the present invention may be selected
from natural products such as essential oils, absolutes, resinoids, resins, concretes,
and synthetic perfume components such as hydrocarbons, alcohols, aldehydes, ketones,
ethers, acids, acetals, ketals and nitriles, including saturated and unsaturated compounds,
aliphatic, carbocyclic and heterocyclic compounds, or precursors of any of the above.
Other examples of odorant compositions which may be used are described in H 1468 (United
States Statutory Invention Registration).
[0046] Examples of preferred fragrance components are any of those fragrances selected from
Agrumex, Aldron, Ambrettolide, Ambroxan, benzyl cinnamate, benzyl salicylate, Boisambrene,
cedrol, cedryl acetate, Celestolide / Crysolide, Cetalox, citronellyl ethoxalate,
Fixal, Fixolide, Galaxolide, Guaiacwood Acetate, cis-3-hexenyl salicylate, hexyl cinnamic
aldeliyde, hexyl salicylate, Iso E Super, linalyl benzoate, linalyl cinnamate, linalyl
phenyl acetate, Javanol, methyl cedryl ketone, Moskene, Musk, Musk Ketone, Musk Tibetine,
Musk Xylol, Myraldyl Acetate, nerolidyl acetate, Novalide, Okoumal, para-cresyl caprylate,
para-cresyl phenyl acetate, Phantolid, phenyl ethyl cinnamate, phenyl ethyl salicylate,
Rose Crystals, Rosone, Sandela, tetradecanitrile, Thibetolide, Traseolide, Trimofix
O, 2-methyl pyrazine, acetaldehyde phenylethyl propyl acetal, acetophenone, alcohol
C6 (in the following the notation Cn comprises all substances having n carbon atoms
and one hydroxyl function), alcohol C8, aldehyde C6 (in the following the notation
Cn encompasses all isomers having n carbon atoms and one aldehyde function), aldehyde
C7, aldehyde C8, aldehyde C9, nonenylic aldhyde, allyl amyl glycolate, allyl caproate,
amyl butyrate, aldehyde anisique, benzaldehyde, benzyl acetate, benzyl acetone, benzyl
alcohol, benzyl butyrate, benzyl formate, benzyl iso-valerate, benzyl methyl ether,
benzyl propionate, Bergamyl Acetate, butyl acetate,camphor, 3-methyl-5-propyl-2-cyclohexenone,
cinnamic aldehyde, cis-3-hexenol, cis-3-hexenyl acetate, cis-3-hexenyl formate, cis-3-hexenyl
iso-butyrate, cis-3-hexenyl propionate, cis-3-hexenyl tiglate, citronellal, citronellol,
citronellyl nitrile, 2-hydroxy-3-methyl-2-cyclopenten-1-one, cuminic aldehyde, Cyclal
C, acetic acid (cycloheyloxy)-2-propenylester, damascenone, alpha-damascone, beta-damascone,
decahydro beta-napthyl formate, diethyl malonate, dihydro-jasmone, dihydro-linalool,
dihydro-myrcenol, dihydroterpineol, dimethyl anthranilate, dimethyl benzyl carbinol,
dimethyl benzyl carbinyl acetate, dimethyl octenone, Dimetol, dimyrcetol, estragole,
ethyl acetate, ethyl acetoacetate, ethyl benzoate, ethyl heptoate, ethyl linalool,
ethyl salicylate, ethyl-2-methyl butyrate, eucalyptol, eugenol, fenchyl acetate, fenchyl
alcohol, 4-phenyl-2,4,6-trimethyl 1,3-dioxane, methyl 2-octynoate, 4-isopropylcyclohexanol,
2-sec-butylcyclohexanone, styralyl acetate, geranyl nitrile, hexyl acetate, alpha-ionone,
iso-amyl acetate, iso-butyl acetate, iso-cyclocitral, dihydroisojasmone, iso-menthone,
iso-pentyrate, iso-pulegol, cis-jasmone, laevo-carvone, phenylacetaldehyde glycerylacetal,
carbinic acid 3 -hexenyl methyl ether, 1-methyl-cyclohexa-1,3-diene, linalool, linalool
oxide, 2-ethyl ethyl ester pentanoate, 2,6-dimethyl-5-heptenal, menthol, menthone,
methyl acetophenone, methyl amyl ketone, methyl benzoate, alpha-methyl cinnamic aldehyde,
methyl heptenone, methyl hexyl ketone, methyl para cresol, methyl phenyl acetate,
methyl salicylate, Neral, Nerol, 4-tert-pentyl-cyclohexanone, para-cresol, para-cresyl
acetate, para-t-butyl cyclohexanone, para-toluyl aldehyde, phenyl acetaldehyde, phenyl
ethyl acetate, phenyl ethyl alcohol, phenyl ethyl butyrate, phenyl ethyl formate,
phenyl ethyl iso butyrate, phenyl ethyl propionate, phenyl propyl acetate, phenyl
propyl aldehyde, tetrahydro-2,4-dimethyl-4-pentyl-furan, 4-methyl-2-(2-methyl-1-propenyl)tetrahydropyran,
5-methyl-3-heptanone oxime, styralyl propionate, styrene, 4-methylphenylacetaldehyde,
terpineol, terpinolene, tetrahydro-linalool, tetrahydro-myrcenol, trans-2-hexenal,
verdyl acetate and Viridine.
[0047] In a preferred embodiment of the present invention, the encapsulated fragrance comprises
at least 70 wt% of fragrance components having a loss factor higher than 10
2 Pa ppm, most preferably higher than 10
4 Pa ppm. The term "Loss Factor" refers to a parameter that is related to the losses
of fragrance material during drying and is defined as the product of the pure component
vapour pressure (Pa) and the water solubility (ppm) at room temperature. Vapour pressures
and water solubility data for commercially available fragrance components are well
known and so the Loss Factor for a given fragrance component may be easily calculated.
Alternatively, vapour pressure and water solubility measurements may be easily taken
using techniques well known in the art. Vapour pressure of fragrance components may
be measured using any of the known quantitative headspace analysis techniques, see
for example
Mueller and Lamparsky in Perfumes: Art, Science and Technology, Chapter 6 "The Measurement
of Odors" at pages 176 -179 (Elsevier 1991). The water solubility of fragrances may be measured according to techniques known
in the art for the measurement of sparingly water-soluble materials. A preferred technique
involves the formation of a saturated solution of a fragrance component in water.
A tube with a dialysed membrane is placed in the solution such that after equilibration
an idealised solution is formed within the tube. The tube may be removed and the water
solution therein extracted with a suitable organic solvent to remove the fragrance
component. Finally the extracted fragrance component may be concentrated and measured,
for example using gas chromatography. Other methods of measuring fragrances are disclosed
in
Gygax et al, Chimia 55 (2001) 401-405.
[0048] Preferred fragrances having high loss factor may be selected from 2-methyl pyrazine,
acetaldehyde phenylethyl propyl acetal, acetophenone, alcohol C6 (in the following
the notation Cn comprises all substances having n carbon atoms and one hydroxyl function),
alcohol C8, aldehyde C6 (in the following the notation Cn encompasses all isomers
having n carbon atoms and one aldehyde function), aldehyde C7, aldehyde C8, aldehyde
C9, nonenylic aldhyde, allyl amyl glycolate, allyl caproate, amyl butyrate, aldehyde
anisique, benzaldehyde, benzyl acetate, benzyl acetone, benzyl alcohol, benzyl butyrate,
benzyl formate, benzyl iso-valerate, benzyl methyl ether, benzyl propionate, bergamyl
acetate, autyl acetate, camphor, 3-methyl-5-propyl-2-cyclohexenone, cinnamic aldehyde,
cis-3-hexenol, cis-3-hexenyl acetate, cis-3-hexenyl formate, cis-3-hexenyl iso-butyrate,
cis-3-hexenyl propionate, cis-3-hexenyl tiglate, citronellal, citronellol, citronellyl
nitrile, 2-hydroxy-3-methyl-2-cyclopenten-1-one, cuminic aldehyde, cyclal C, acetic
acid (cycloheyloxy)-2-propenylester, damascenone, alpha-damascone, beta-damascone,
diethyl malonate, dihydro jasmone, dihydro linalool, dihydro myrcenol, dihydro terpineol,
dimethyl anthranilate, dimethyl benzyl carbinol, dimethyl benzyl carbinyl acetate,
dimethyl octenone, dimetol, dimyrcetol, estragole, ethyl acetate, ethyl aceto acetate,
ethyl benzoate, ethyl heptoate, ethyl linalool, ethyl salicylate, ethyl-2-methyl butyrate,
eucalyptol, eugenol, fenchyl acetate, fenchyl alcohol, 4-phenyl-2,4,6-trimethyl 1,3-dioxane,
methyl 2-octynoate, 4-isopropylcyclohexanol, 2-sec-butylcyclohexanone, styralyl acetate,
geranyl nitrile, hexyl acetate, alpha-ionone, iso-amyl acetate, iso-butyl acetate,
iso-cyclocitral, dihydroisojasmone, iso-menthone, iso-pentyrate, iso-pulegol, cis-jasmone,
laevo carvone, phenylacetaldehyde glycerylacetal, carbinic acid 3 hexenyl methyl ether,
1-methyl-cyclohexa-1,3-diene, linalool, linalool oxide, 2,6-dimethyl-5-heptenal, menthol,
menthone, methyl acetophenone, methyl amyl ketone, methyl benzoate, methyl cinnamic
aldehyde alpha, methyl heptenone, methyl hexyl ketone, methyl para-cresol, methyl
phenyl acetate, methyl salicylate, neral, nerol, 4-tert-pentyl-cyclohexanone, para-cresol,
para-cresyl acetate, para-t-butyl cyclohexanone, para-tolyl aldehyde, phenyl acetaldehyde,
phenyl ethyl acetate, phenyl ethyl alcohol, phenyl ethyl butyrate, phenyl ethyl formate,
phenyl ethyl iso-butyrate, phenyl ethyl propionate, phenyl propyl acetate, phenyl
propyl aldehyde, tetrahydro-2,4-dimethyl-4-pentyl-furan, 4-methyl-2-(2-methyl-1-propenyl)tetrahydropyran,
5-methyl-3-heptanone oxime, styralyl propionate, styrene, 4-methylphenylacetaldehyde,
terpineol, terpinolene, tetrahydro linalool, tetrahydro myrcenol, trans-2-hexenal,
and Viridine.
[0049] In a further specific embodiment of the present invention, the fragrance components
may have an odour value higher than 10'000. The odor value is defined as the standard
headspace concentration
of odorant in thermodynamic equilibrium with this odorant in the standard state (278.15
K, 1 atmosphere), expressed in microgram / 1 headspace, divided by the olfactory threshold
of this odorant (in microgram / 1 headspace) as measured by olfactometry. The standard
headspace concentration is related to the vapor pressure of the pure ingredient by
the equation:
where
is the molar mass of the odorant, R is the gas constant,
T the absolute temperature given in Kelvin and
the standard vapour pressure given in atmosphere.
[0050] Precursor of fragrance components may also be provided in fragrance materials in
the present invention. Precursors are compounds that, upon cleavage under activating
conditions such as light, enzymes, elevated temperature or acidic or alkaline pH-values,
provide compounds having fragrance characteristics.
[0051] Furthermore, other organoleptic materials may be used in admixture with fragrance
ingredients, for example, odour-masking agents, insect repellents and the like.
[0052] The amount of fragrance possible to be micro-encapsulated is generally superior to
85 wt%, and even superior to 95 wt%, based on dry material, with a micro-encapsulation
yield close or superior to 80 wt%, even for the very volatile components having a
Loss Factor of greater than 10
2 Pa ppm.
In a further specific embodiment, 1% to 100%, preferably 20% to 90% and most preferably
25% to 75% of the fragrance components may have a clogP, the logarithm of calculated
octanol / water partition coefficient, value not larger than 4.5, preferably between
2 and 4.5, most preferably between 3 and 4.5.
[0053] The amount of fragrance composition employed in perfumed products or articles according
to the present invention may vary according to the particular application in which
it is employed and on the fragrance loading in the fragrance composition. For laundry
applications, one may employ fragrance composition in amounts from 0.01 to 3% by weight
of fragrance material based on the total weight of the laundry care product.
[0054] The microcapsules according to the invention are especially useful in personal care
and household, washing and cleaning products, such as soaps, shampoos, skin care creams,
laundry detergents, fabric conditioners, dishwashing liquids, furniture polishes and
the like. The invention therefore provides a personal care product, a household product,
a washing product or a cleaning product, comprising a composition that comprises microcapsules
as hereinabove defined.
[0055] There now follows a series of Examples that serve to illustrate embodiments of the
present invention. It will be understood that these Examples are illustrative, and
the invention is not to be considered as being restricted thereto.
Ex 1: Preparation of microcapsules
1.1 Preparation of capsules according to the prior art
[0056] The following example illustrates the formation of a modified melamine-formaldehyde
microcapsules, using resorcinol as co-monomer. 24.17 g of Lupasol PA140 (ex BASF),
26.25 g of Luracoll SD (ex BASF) was added to 250 g of water in a 11 jacket reactor.
The stirring velocity was adjusted to reach the required particles size and the mixture
was heated to a first temperature (35 °C). 200 g of test perfume (table I) were then
added to the mixture which was maintained under continuous agitation to allow the
formation of an emulsion. The polymerization was started by adjusting the pH value
to 3.5 using a 10% solution of formic acid. 12 g of resorcinol (30% solution in water)
was added. The reaction temperature was then raised to 75 °C for 90 minutes, in order
to achieve complete cross-linking of the microcapsule shell (curing). After 1 hour
curing the pH value was adjusted to pH 3.5 by using a formic acid. After 90 minutes
the reaction was cooled down and the pH value was adjusted to 9.3 using ammonia.
Table I: Composition of test perfume oil
Fragrance Ingredient |
Percentage in Formula |
Verdox |
4.86 |
anisic aldehyde |
0.73 |
Benzophenone |
1.46 |
Benzyl acetate |
0.59 |
Benzyl salicylate |
2.88 |
beta-ionone |
18.85 |
beta-pinene |
0.45 |
brassylate ethylene |
0.59 |
cis-3-hexenyl salicylate |
0.45 |
Coumarine |
0.59 |
cyclal C |
2.25 |
Eugenol |
0.59 |
Galbanone |
3.47 |
Habanolide |
0.59 |
Hedione |
0.59 |
hexyl acetate |
1.73 |
hexyl cinnamic aldehyde |
5.76 |
Iso E super |
11.01 |
Isoraldeine |
5.10 |
Lilial |
5.83 |
Linalol |
1.35 |
Linalyl acetate |
1.46 |
Nectaryl |
3.47 |
Oranger |
2.88 |
beta-decalactone |
3.47 |
Phenyl ethyl acohol |
2.32 |
Prenyl acetate |
1.04 |
Rosacetol |
1.15 |
Rosaphen |
0.87 |
Thibetolide |
0.59 |
Verdyl acetate |
11.28 |
Verdyl propionate |
0.87 |
Vertofix |
0.87 |
Total |
100.00 |
1.2 Using dimethoxyethanal-melamine pre-condensate
[0057] The following example illustrates the formation of melamine - based microcapsules
according to the present invention, using dimethoxyethanal-melamine pre-condensate
as source of terpolymer methylene moieties, using a terpolymer comprising various
co-monomer selected from amino compounds, aliphatic, aromatic and polymeric polyols.
8.10 g Gantrez AN 169 BF (ex ISP) was added to 250 g of water in a 11 jacket reactor
and heated up to 80°C for 45 minutes until a clear solution is obtained. A solution
of 55.89 g of Highlink CDO (ex Clariant) and 20.4 g of resorcinol (30% solution) were
added. The stirring velocity was adjusted to reach the required particles size and
the mixture was heated to a first temperature (35 °C). 200g of test perfume were then
added to the mixture which was maintained under continuous agitation to allow the
formation of an emulsion. The polymerization was started by adjusting the pH value
to 5.2 using a 10% solution of formic acid. The reaction temperature was then raised
to 75°C for 90 minutes, in order to achieve complete cross-linking of microcapsule
shell (curing). After 1 hour curing the pH value was adjusted to pH 3.5 by using a
formic acid. After 90 minutes the reaction was cooled down and the pH value was adjusted
to 8 using ammonia.
1.3 Using methylglyoxylatemethylhemiacetal (GMHA)
[0058] The following example illustrates the formation of new formaldehyde-free melamine-based
microcapsules according to the present invention, using GMHA as source of terpolymer
methylene moieties. A mixture of 20.4 g melamine, 18 g GMHA (ex. DSM) 5.6 g resorcinol
and 12 g of water were heated up 80°C for 10 minutes until a clear solution is obtained.
Separately an emulsion comprising 200 g water, 200 g test perfume and 2 g polymer
stabilizer was prepared in a 11 jacket reactor. The stirring velocity was adjusted
to reach the required particles size and the mixture was heated to a first temperature
(35 °C). After adding the solution of melamine, GMHA and resorcinol, the reaction
temperature was raised to 80 °C in order to start the polymerization. After 240 minutes
the reaction was cooled down to room temperature.
Example 2: Determination of formaldehyde
[0059] The residual free formaldehyde level in the microcapsule slurry is determined by
high-performance-liquid-chromatography (HPLC) according to Method 8315A of the Environmental
Protection Agency (EPA). Hereunto, depending on the expected amount of free formaldehyde,
100 mg to 1 g of slurry is weighted in a 10 ml flask and the volume completed with
water. The solution/suspension is exposed for 10 minutes to an ultrasonic bath. The
microcapsules are separated from the liquid phase by filtration or centrifugation.
Derivatization of the free formaldehyde is achieved by mixing 3 µl of the liquid phase
with 6 µl of a solution of 2,4-dinitro-phenylhydrazine DNPH at 1 wt% in acetonitrile.
The analysis is carried out by injecting this mixture in an Agilent 1100 HPLC system
equipped with an UV diode-array detector (DAD). Typical results are summarized in
Table I.
Table I: Impact of methylene moiety selection on total formaldehyde level.
Sample # |
HCHO level in the slurry [ppm] |
Example 1.1 |
370 |
Example 1.2 |
Not detectable |
Example 1.3 |
Not detectable |
1. Microcapsules comprising a core of fragrance and a shell of aminoplast polymer, the
composition of the shell being from 75-100% of a thermoset resin comprising 50-90%,
preferably from 60-85%, of a terpolymer and from 10-50%, preferably from 10-25%, of
a polymeric stabilizer; the terpolymer comprising:
(a) from 20-60%, preferably 30-50% of moieties derived from at least one polyamine;
(b) from 3-50%, preferably 5-25% of moieties derived from at least one polyol; and
(c) from 20-70%, preferably 40-60% of substituted methylene moieties,
the microcapsules additionally optionally comprising up to 25%, preferably up to 10%
of a cationic polymer;
the substituted methylene moieties have the general formula (1)
in which R is either a hydrogen atom or an alkyl group and Y
1 and Y
2 are substituents selected from sigma acceptor groups, alkyne groups and metal sulphonates.
2. Microcapsules according to claim 1, in which the polyamine moieties are derived from
at least one of urea, melamine, 6-substituted 2,4-diamino-1,3,5-triazin and glycoluril.
3. Microcapsules according to claim 1, in which the polyol moieties are derived from
at least one of phenol, 3,5-dihydroxy toluene, Bisphenol A, resorcinol, hydroquinone,
xylenol, polyhydroxy naphthalene, polyphenols produced by the degradation of cellulose
and humic acids, 2,2-dimethyl-1,3-propane diol, 1,1,1-tris-(hydroxymethyl)-propane,
pentaerythritol, sorbitol and sugars.
4. Microcapsules according to claim 1, in which the substituted methylene moieties are
derived from at least one compound having a formula selected from formulae (2) and
(3)
wherein R
1 is either a hydrogen atom or an alkyl group and Y
1 and Y
2 are substituents selected from sigma acceptor groups, alkyne groups and metal sulphonates.
5. Microcapsules according to claim 1, in which the polymeric stabilizer is an anionic
polyelectrolyte.
6. Microcapsules according to claim 1, in which there is present a cationic polymer,
selected from the group consisting of cationic cellulose derivatives, quaternized
gums, polyethylene imine, cationic polyacrylates and acrylamides , gelatine and quaternized
protein hydrolysates, and quaternized amino silicones.
7. A fragranced personal care, household, washing and cleaning product comprising microcapsules
according to claim 1.
8. A product according to claim 7, selected from laundry solid and liquid detergents
and liquid fabric softeners and conditioners.
9. A product according to claim 8, in which the product contains free perfume.
10. A product according to claim 9, in which the free perfume differs in strength and/or
quality from the encapsulated perfume.
11. A fabric conditioner according to claim 8, in which the microcapsules are present
in an anionic form.
1. Mikrokapseln mit einem Duftstoffkern und einer Aminoplastpolymerschale, wobei sich
die Schale aus 75-100% eines Duroplastharzes, das 50-90%, vorzugsweise 60-85%, eines
Terpolymers und 10-50%, vorzugsweise 10-25%, eines polymeren Stabilisators umfasst,
wobei das Terpolymer:
(a) 20-60%, vorzugsweise 30-50%, Gruppierungen, die sich von mindestens einem Polyamin
ableiten;
(b) 3-50%, vorzugsweise 5-25%, Gruppierungen, die sich von mindestens einem Polyol
ableiten; und
(c) 20-70%, vorzugsweise 40-60%, substituierte Methylengruppierungen
umfasst, zusammensetzt, wobei die Mikrokapseln zusätzlich gegebenenfalls bis zu 25%,
vorzugsweise bis zu 10%, eines kationischen Polymers umfassen; die substituierten
Methylengruppierungen die allgemeine Formel (1)
aufweisen, wobei R entweder für ein Wasserstoffatom oder für eine Alkylgruppe steht
und Y
1 und Y
2 für Substituenten stehen, die aus Sigma-Akzeptorgruppen, Alkingruppen und Metallsulfonaten
ausgewählt sind.
2. Mikrokapseln nach Anspruch 1, wobei sich die Polyamingruppierungen von Harnstoff,
Melamin, 6-substituiertem 2,4-Diamino-1,3,5-triazin und/oder Glykoluril ableiten.
3. Mikrokapseln nach Anspruch 1, wobei sich die Polyolgruppierungen von Phenol, 3,5-Dihydroxytoluol,
Bisphenol A, Resorcin, Hydrochinon, Xylenol, Polyhydroxynaphthalin, durch den Abbau
von Cellulose und Huminsäuren gebildeten Polyphenolen, 2,2-Dimethyl-1,3-propandiol,
1,1,1-Tris(hydroxymethyl)propan, Pentaerythrit, Sorbit und/oder Zuckern ableiten.
4. Mikrokapseln nach Anspruch 1, wobei sich die substituierten Methylengruppierungen
von mindestens einer Verbindung mit einer aus den Formeln (2) und (3) ausgewählten
Formel ableiten:
wobei R
1 entweder für ein Wasserstoffatom oder für eine Alkylgruppe steht und Y
1 und Y
2 für Substituenten stehen, die aus Sigma-Akzeptorgruppen, Alkingruppen und Metallsulfonaten
ausgewählt sind.
5. Mikrokapseln nach Anspruch 1, wobei es sich bei dem polymeren Stabilisator um einen
anionischen Polyelektrolyt handelt.
6. Mikrokapseln nach Anspruch 1, wobei ein kationisches Polymer aus der Gruppe bestehend
aus kationischen Cellulosederivaten, quaternisierten Gummen, Polyethylenimin, kationischen
Polyacrylaten und Acrylamiden, Gelatine und quaternisierten Proteinhydrolysaten und
quaternisierten Aminosilikonen vorhanden ist.
7. Duftstoffhaltiges Körperpflege-, Haushalts-, Wasch- und Reinigungsprodukt, umfassend
Mikrokapseln nach Anspruch 1.
8. Produkt nach Anspruch 7, ausgewählt unter festen und flüssigen Waschmitteln und flüssigen
Weichspülern.
9. Produkt nach Anspruch 8, wobei das Produkt freies Parfüm enthält.
10. Produkt nach Anspruch 9, wobei sich das freie Parfüm hinsichtlich Stärke und/oder
Qualität von dem verkapselten Parfüm unterscheidet.
11. Weichspüler nach Anspruch 8, wobei die Mikrokapseln in anionischer Form vorliegen.
1. Microcapsules comprenant un coeur de fragrance et une écorce d'un polymère aminoplaste,
la composition de l'écorce étant constituée de 75-100% d'une résine thermodurcie comprenant
50-90%, préférablement 60-85%, d'un terpolymère et 10-50%, préférablement 10-25%,
d'un stabilisant polymère ; le terpolymère comprenant :
(a) 20-60%, préférablement 30-50%, de motifs dérivés d'au moins une polyamine ;
(b) 3-50%, préférablement 5-25%, de motifs dérivés d'au moins un polyol ; et
(c) 20-70%, préférablement 40-60%, de motifs méthylène substitués ;
les microcapsules comprenant éventuellement de plus jusqu'à 25%, préférablement jusqu'à
10%, d'un polymère cationique ;
les motifs méthylène substitués répondant à la formule générale (1)
dans laquelle R est un atome d'hydrogène ou bien un groupement alkyle et Y
1 et Y
2 sont des substituants choisis parmi des groupements accepteurs sigma, des groupements
alcyne et des sulfonates de métaux.
2. Microcapsules selon la revendication 1, dans lesquelles les motifs de polyamine sont
dérivés d'au moins l'un parmi l'urée, la mélamine, la 2,4-diamino-1,3,5-triazine 6-substituée
et le glycolurile.
3. Microcapsules selon la revendication 1, dans lesquelles les motifs de polyol sont
dérivés d'au moins l'un parmi le phénol, le 3,5-dihydroxytoluène, le bisphénol A,
le résorcinol, l'hydroquinone, le xylénol, le polyhydroxynaphtalène, les polyphénols
produits par la dégradation de cellulose et d'acides humiques, le 2,2-diméthyl-1,3-propanediol,
le 1,1,1-tris(hydroxyméthyl)propane, le pentaérythritol, le sorbitol et les sucres.
4. Microcapsules selon la revendication 1, dans lesquelles les motifs méthylène substitués
sont dérivés d'au moins un composé répondant à une formule choisie parmi les formules
(2) et (3)
dans lesquelles R
1 est un atome d'hydrogène ou bien un groupement alkyle et Y
1 et Y
2 sont des substituants choisis parmi des groupements accepteurs sigma, des groupements
alcyne et des sulfonates de métaux.
5. Microcapsules selon la revendication 1, dans lesquelles le stabilisant polymère est
un polyélectrolyte anionique.
6. Microcapsules selon la revendication 1, dans lesquelles est présent un polymère cationique,
choisi dans le groupe constitué par les dérivés de cellulose cationiques, les gommes
quaternisées, la polyéthylèneimine, les polyacrylates et acrylamides cationiques,
la gélatine et les hydrolysats protéiques quaternisés, et les silicones aminées quaternisées.
7. Produit parfumé de soin personnel, ménager, de lavage et de nettoyage, comprenant
des microcapsules selon la revendication 1.
8. Produit selon la revendication 7, choisi parmi les détergents solides et liquides
pour le linge et les assouplissants et adoucissants liquides pour le linge.
9. Produit selon la revendication 8, dans lequel le produit contient du parfum libre.
10. Produit selon la revendication 9, dans lequel le parfum libre est différent en termes
de force et/ou de qualité par rapport au parfum encapsulé.
11. Adoucissant pour linge selon la revendication 8, dans lequel les microcapsules sont
présentes sous forme anionique.